check whether 'base' defines a complete program (ie. all version stamps
are defined and consistent, all imported interfaces are defined, 'Main'
is exported). If the units of 'base' form a complete program,
TRUE is returned, otherwise is returned. If there are inconsistencies,
error messages are written on 'errors'. If 'errors' is NIL, the error
messages are silently dropped. It is an unchecked runtime error to
modify any of the units of 'base'.

check whether 'base' defines a complete library (ie. all version stamps
are defined and consistent, all imported interfaces are defined, ...).
If the units of 'base' form a complete library, TRUE is returned,
otherwise FALSE is returned. If there are inconsistencies, error
messages are written on 'errors'. If 'errors' is NIL, the error
messages are silently dropped. It is an unchecked runtime error to
modify any of the units of 'base'.